Coupling arrangement for rail vehicles

ABSTRACT

A coupling arrangement for coupling together rail vehicles such as railway carriages and locomotives consisting of a coupling head comprising a coupling housing ( 1 ) joined to the rail vehicle and having an active coupling device in the form of a plunger ( 2 ) movable between an outer and an inner position and designed to co-operate with a similar plunger in a corresponding coupling head when two coupling heads are coupled together, the plungers ( 2 ) being movable in directions that are substantially perpendicular to the longitudinal directions of the coupling heads and can be released at uncoupling. A locking device ( 7 ) is provided in the coupling arrangement and comprises a locking member ( 7.5 ) arranged to be brought into contact with the plunger ( 2 ) when this is in its outer position and to prevent the plunger ( 2 ) being displaced from this position.

TECHNICAL FIELD

The present invention relates to a coupling arrangement for couplingtogether rail vehicles such as railway carriages and locomotives,consisting of a coupling head comprising a coupling housing joined tothe rail vehicle and having an active coupling device in the form of aplunger movable between an outer and an inner position and designed toco-operate with a similar plunger in a corresponding coupling head whentwo coupling heads are coupled together.

BACKGROUND ART

In automatic coupling of rail vehicles such as railway carriages,locomotives and the like, coupling arrangements are used that permitcarriages, etc. to be coupled together regardless of which end of thecarriage is facing the carriage with which it is to be coupled. Suchcoupling arrangements comprise a coupling housing connected to the railvehicle and having an active coupling member in the form of a plungerdesigned to co-operate with a similar plunger in a correspondingcoupling head when these are coupled together. Each plunger has asurface that is inclined to the longitudinal direction of the couplinghead and a load-absorbing contact surface perpendicular to thisdirection. When the two coupling heads are united, the inclined surfacesare brought into contact with each other, whereupon the plungers aredisplaced in opposite directions until the two contact surfaces havebeen aligned so that the plungers can return and be brought intoengagement with each other. Such a coupling arrangement is manufacturedby SAB WABCO BSI Verkehrstechnic GmbH, Germany.

The disadvantage with the known coupling arrangement is that, after sometime in use, the load-absorbing contact surfaces of the plunger, as wellas other components in the coupling head, become worn. Railway tracksare usually not so smooth that carriages and locomotives can be drivenalong them without vibration and twisting, which subject the couplingheads to considerable strain. It has been found that coupling heads thathave been subjected to a certain amount of wear lose theirload-transmitting function when subjected to such strain, i.e. theplungers lose their grip on each other. The connection between carriagesor between carriage and locomotive is consequently broken and the trainunit is automatically braked and comes to a standstill. Other reasonsfor such coupling heads losing their function are that the springretaining the plunger in engagement position breaks or becomes fatigued,or that two plungers do not achieve correct engagement with each other.Since this type of automatic coupling arrangement is widely used, agreat need exists to improve its function as regards ensuring that thecoupling heads do not unintentionally separate during use.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a coupling arrangementthat does not have the drawbacks of the existing coupling arrangementdescribed above. The object is achieved with a coupling arrangementconsisting of a coupling head comprising a coupling housing joined tothe rail vehicle and having an active coupling device in the form of aplunger movable between an outer and an inner position and designed tocooperate with a similar plunger in a corresponding coupling head whentwo coupling heads are coupled together. The plungers are movable indirections that are substantially perpendicular to the longitudinaldirections of the coupling heads and can be moved away from each otherby mutual contact at interlocking, and with the aid of a disengagingmeans for each plunger when a train unit is being uncoupled.

To prevent the plungers being unintentionally separated when theircontact surfaces have become worn to a certain extent, or when ruptureor fatigue occurs in the plunger springs, a locking device is providedin each coupling arrangement and comprises a locking member arranged tobe brought into contact with the plunger when this is in its outerposition and to prevent the plunger being displaced from this position.

In a preferred embodiment of the invention the locking arrangement isprovided with a toggle joint comprising two locking links which arehingeably joined and placed in a locking housing and which, when theplunger is in locked position, are aligned in one and the same plane,the outer part of one link resting against the locking housing and theouter part of the other link resting against the locking member, thustransmitting a force between the locking member and the locking housing.The locking links can be turned in relation to each other and foldedabout a hinge so that their outer ends are moved towards each other.When the locking links are folded in this manner theirforce-transmitting influence on the locking member ceases and the lattercan therefore be disengaged from its contact with the plunger so thatthis is released.

The locking member may consist of a roller which, upon locking, isdisplaced directly or indirectly at right angles to its longitudinaldirection in a channel in the locking housing in a direction towards theplunger to engage with a corresponding recess in its outer shell.

With the object of being able to operate the locking arrangement betweenlocked and disengaged position an actuating rod is arranged to extendthrough the locking arrangement and is connected to the locking links.One end of the actuating rod is connected to a piston in an operatingcylinder which, when pressurised by means of a hydraulic or pneumaticpressure medium, causes the locking links to press the locking member toengagement with the plunger.

However, the invention is not limited to a locking arrangementcomprising a toggle joint and many embodiments are feasible instead.

In a first alternative embodiment of the locking arrangement inaccordance with the invention, the locking member may be influenced by alinearly movable wedge, which, upon contact, presses the locking memberagainst the plunger. The wedge is connected to an actuating rod of thetype described above.

In a second alternative embodiment of the locking arrangement inaccordance with the invention the locking member may consist of a rodactivated by a servo device e.g. a compressed air cylinder, with the aidof which the rod can be inserted into a hole in the plunger when this isin its outer position, thereby locking the plunger against undesireddepression. The servo device is only activated after connection has beenperformed so that the rod engages with the plunger. The rod may bespring-loaded and returns to its original position as soon as the servodevice is disconnected. Alternatively the rod may be spring-loaded inthe starting position and automatically engage with the plunger whenthis is pressed in, and is disengaged with the aid of the servo device.

In a third alternative embodiment of the locking arrangement inaccordance with the invention the locking member may consist of a latchthat can be turned between a disengaged position in which the plunger isfreely movable, and a locked position in which the latch is incommunication with a recess in the plunger. The latch can be actuated bya servo device in the same way as for the rod as mentioned above.

In a fourth alternative embodiment of the locking arrangement inaccordance with the invention the locking member may consist of aturnable rod that extends through a recess in the shell of the plunger,the rod having a recess extending to its centre. When the rod is turnedso that its recess is directed towards the plunger the latter can movefreely, but when the rod is turned so that its solid part is incommunication with the recess in the plunger the latter is locked. Thisturnable rod can be actuated by a servo device.

Additional alternative solutions as regards the design of the lockingarrangement are feasible within the scope of the invention, whichrelates to all forms of locking members that can be brought into contactwith and firmly retain the plunger when this is in its outer position,and prevent the plunger, due to wear, broken or fatigued springs and thelike, releasing its grip on the plunger in the corresponding couplinghead. The choice of solution as regards the locking member is determinedto a certain extent by the design of the rest of the couplingarrangement and how much space is available for the locking arrangement,which in turn is determined by the demands placed on its function.

Additional details and features pertaining to the preferred embodimentof the invention are revealed in the description of the drawings andalso in the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

One embodiment of the invention is described in the following by way ofexample with reference to the accompanying drawings.

FIG. 1 shows a coupling arrangement in accordance with known technology,in a horizontal section, which has not been modified in accordance withthe present invention.

FIG. 2 shows schematically, also in a horizontal section, the activecoupling parts in a coupling arrangement in disengaged position, thecoupling arrangement having been modified in accordance with theinvention.

FIG. 3 shows the coupling parts in accordance with FIG. 2 in lockedposition

FIG. 4 shows a locking link on its own, in the position shown in FIG. 2.

FIG. 5 shows the locking link on its own, in the position shown in FIG.3.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The coupling arrangement shown in FIG. 1 is manufactured by SAB WABCOBSI Verkehrstechnic GmbH, Germany, and is generally used for automaticcoupling of rail vehicles such as railway carriages and locomotives. Thecoupling arrangement consists of a coupling head comprising a couplinghousing 1 joined to the rail vehicle, not shown in the figure, andhaving an active coupling device in the form of a plunger 2 designed toco-operate with a similar plunger in a corresponding coupling head whenthese are coupled together. The plunger 2 is tubular and has a closedouter end with a hook-shaped part having coupling surfaces consisting ofa surface 2.1 inclined to the longitudinal direction of the couplinghead and a load-absorbing contact surface 2.2 perpendicular to thisdirection. The plunger 2 is held by spring force, pressed in towards thecenter of the coupling head by means of a helical spring 2.3 arrangedinside the plunger 2. At the front end of the coupling housing 1 is aforwardly protruding nose-shaped member 3 designed to engage with acorresponding recess 4 when two coupling heads are coupled together. Thespring 2.3 in the plunger 2 rests partly against the closed end of theplunger 2 with its coupling surfaces 2.1, 2.2 and also against a pin 2.4which extends down through the plunger 2 in oblong grooves 2.5 in itsenvelope or shell surface, and which is secured in the coupling housing1 on each side of the plunger 2.

When two coupling heads are united, the nose member 3 rests againstinner support surfaces in the recess 4 while the inclined surfaces 2.1in the two co-operating plungers 2 are brought into contact with eachother. The plungers are thus displaced outwardly from the centre of thecoupling head until the two contact surfaces 2.2 have been aligned sothat the plungers 2 can return and be brought into engagement with eachother.

Two united coupling heads are disengaged from each other by at least oneof the plungers 2 being pulled out of contact with the other by means ofa disengaging lever 5 which is hinged to the plunger via a pin 5.1, oneend resting against a counter-support 1.1 on the coupling head 1. Thedisengaging lever 5 is influenced at one end by a pneumatic disengagingcylinder 6 having a piston 6.1 which, when the cylinder 6 is placedunder pressure, protrudes and turns the disengaging lever 5 about thecounter-support 1.1 which thus pulls in the plunger 2 against the forceof the spring 2.3 therein.

The coupling arrangement in accordance with the invention, shown in FIG.2, has substantially the same function as the known arrangement shown inFIG. 1 and, like this, comprises a coupling housing 1 that houses anactive coupling member in the form of a plunger 2 designed to co-operatewith a similar plunger in a corresponding coupling head. FIG. 2 showsthe plunger 2 in its inner position, i.e. at the moment when twoco-operating plungers are just about to pass each other in a couplingstage between two coupling heads. In the position shown in FIG. 2 thelocking arrangement 7 is not activated and the plunger 2 can thereforemove freely in its bore. The coupling arrangement in accordance with theinvention is provided with a locking device 7 designed to lock theplunger 2 in its outer position, as shown in FIG. 3, i.e. when twocoupling heads are coupled together to transmit a tensile force betweenthe contact surfaces 2.2 of the plungers.

The active parts of the locking device 7 are shown separately in FIG. 4and consist of a toggle joint comprising two locking links 7.1 which arejoined by a linking pin 7.2 and hingeable in relation to each other sothat the locking links 7.1 can be folded about a hinge. The exterior ofeach locking link 7.1 has a semicylindrical outer part and its innerpart has two pairs of lugs 7.3 which co-operate via the through-runninglink pin 7.2. An actuating rod 7.4 is arranged between the locking links7.1 and has a hole through which the link pin 7.2 passes. This hole ispreferably oblong and extends perpendicularly to the longitudinaldirection of the actuating rod 7.4 to prevent the force between thelocking links 7.1 being transmitted to the actuating rod 7.4 which wouldotherwise tend to jam against the link pin 7.2 and become difficult tomove. The locking links 7.1 are housed in a recess 7.6 in a housing 8where the recess 7.6 has an appearance corresponding to the position ofthe locking links 7.1 shown in FIG. 5, which allows the locking links7.1 to be folded about their joint so that their outer parts approacheach other in the recess 7.6. One of the locking links 7.1 is in contactwith a pair of locking rollers 7.5 which are movable at right angles totheir longitudinal direction in a channel 7.7 in the locking housing 8and which constitute the active member that is brought into contact withthe plunger 2 when this is locked fast.

The plunger 2 has a recess 2.6 in the shape of a partial cylinder, inwhich the outer of the locking rollers 7.5 is displaced half way at thelocking movement which consists of the actuating rod 7.4 being displacedfrom the position shown in FIGS. 2 and 4 to the position shown in FIGS.3 and 5. In this position the locking links 7.1 completely fill therecess 7.6 in the housing 8. The locking movement is activated by apneumatic operating cylinder 9 in which a piston 9.1 is movable andwhich is connected via a piston rod 9.2 to the actuating rod 7.4. Whenthe operating cylinder 9 is placed under pressure by compressed airthrough the opening 9.3, the piston 9.1, with the piston rod 9.2, movesthat actuating rod 7.4 from the position shown in FIG. 2 to the positionshown in FIG. 3. Pressurising takes place after connection of the twocoupling heads has been completed and the plunger 2 moved to its outerposition.

When two coupling heads are disengaged, the air pressure in theoperating cylinder decreases to the ambient pressure, whereupon thepiston 9.1 is pressed back to its initial position by means of a spring9.4 arranged on the lower side of the piston 9.1, or by the space belowthe piston being placed under pressure. The piston rod 9.2 then pullsthe actuating rod from the locked position occupied by the lockingdevice 7 as shown in FIG. 3, to the disengaged positioned shown in FIG.2. Disengagement of the locking device 7 can also be achieved bymanually pressing in the end of the actuating rod 7.4 that protrudesfrom an opening in the disengaging lever 5. The actual uncoupling of thetwo co-operating plungers in each coupling head is achieved either bypressurising the disengaging cylinder 6, the piston 6.1 of which thenturns the disengaging lever 5 outwards, or by manually pulling on thedisengaging lever 5, in which case the actuating rod 7.4 may have to bepushed in first and the locking links 7.1 caused to fold so that thelocking member 7.5 is released.

What is claimed is:
 1. A coupling arrangement for coupling together railvehicles such as railway carriages and locomotives, consisting of acoupling head comprising a coupling housing joined to the rail vehicleand having an active coupling device in the form of a plunger movablebetween an outer and an inner position and designed to cooperate with asimilar plunger in a corresponding coupling head when two coupling headsare coupled together, the plungers being movable in directions that aresubstantially perpendicular to the longitudinal directions of thecoupling heads and can be moved away from each other by mutual contactat interlocking, and with the aid of a disengaging means influencingrespective plungers at uncoupling, and a locking device in the couplingarrangement which comprises a locking member arranged to be brought intodirect contact with the plunger when said plunger is in said outerposition and to prevent the plunger being displaced from said outerposition.
 2. A coupling arrangement as claimed in claim 1, wherein thelocking arrangement includes a toggle joint comprising two locking linkswhich are hingeably joined and placed in a locking housing and which,when the plunger is in locked position, are arranged in one and the sameplane and to transmit a force between the locking member and the lockinghousing and which, when the plunger is to be released, are folded abouta hinge so that the locking member can be disengaged from the plunger,thereby releasing the latter.
 3. A coupling arrangement as claimed inclaim 1, wherein the locking arrangement includes a linearly movablewedge which is in connection with the locking member and which, when theplunger is in locked position, keeps the locking member pressed againstthe plunger and which, when the plunger is to be released, is disengagedfrom the plunger.
 4. A coupling arrangement as claimed in claim 2 orclaim 3, wherein the locking member consists of a roller which, uponlocking, is displaced directly or indirectly at a right angle to alongitudinal direction of the roller in a channel in the locking housingin a direction towards the plunger to engage with a corresponding recessin outer shell of the plunger.
 5. A coupling arrangement as claimed inclaim 4, including an actuating rod which extends through the lockingarrangement and is in communication with locking links or wedge, andwherein one end of the actuating rod is connected to a piston in anoperating cylinder which, when pressurised by means of a hydraulicpneumatic pressure medium, causes the locking links or the wedge topress the locking member to engagement with the plunger.
 6. A couplingarrangement as claimed in claim 5, including a return spring located ona non-pressurised side of the piston, enabling the actuating rod to bepulled back to its original position, thereby releasing the lockingmember when the pressure in the pressure medium ceases.
 7. A couplingarrangement as claimed in claim 5, wherein a hydraulic or pneumaticpressure medium is transferred from one to another side of the piston,thus enabling the actuating rod to be pulled back to its initialposition and release the locking member.
 8. A coupling arrangement asclaimed in claim 7, wherein the other end of the actuating rod protrudesfrom the housing and indicates whether the locking arrangement is inlocked or released position, and actuating rod can be pushed in manuallyand release the locking member.